This proposal is a request for funding for a Q-ToF Maxis HD mass spectrometer (Bruker Daltonics) for the University of Utah Mass Spectrometry and Proteomics Core facility. The instrument will serve two primary purposes: 1) replacement of two old, low-performance ESI/MS, and non-functional mass spectrometers with a high-performance instrument that provides advanced research capabilities, and 2) increase sample analysis efficiency and capacity for the Mass Spectrometry and Proteomics Core for approximately 80 to 90 investigators at the University of Utah, annually. Ten major users from the University of Utah, with 19 active NIH-funded grants, have been identified with current and future research projects, which ensures immediate and long-term continued use of the Maxis HD instrument. There are about 70 to 75 additional minor users, all from the University of Utah. The group of major users will utilize the high mass accuracy capabilities for MS and MS/MS data of the Maxis HD. The research projects of the major users vary widely, but applications include: Proteomics (protein ID and protein PTM discovery), protein sequence confirmations and identification of proteolytic cut sites from intact protein molecules, structural characterizaton of modified peptides (natural and synthetic), structural characterization of drugs and other synthetic small molecules, RNA analysis and other nucleic acid investigations, and synthetic peptide/drug conjugate structure work. The Q-ToF Maxis HD is a high-performance mass spectrometer that provides high sensitivity, high mass accuracy, high resolving power, and versatility for both MS and MS/MS applications, but at the same time, it's relatively easy to operate and is a dependable, workhorse mass spectrometer that is well-suited for the environment of a mass spectrometry core facility. The Q-ToF Maxis HD instrument will be housed in the MS and Proteomics Core facility, a central mass spectrometry shared resource. The MS Core is administered by the Institution, within a well-structured Core Research Facilities framework, including Oversight and Advisory committees. There is very strong Institutional financial support to ensure long-term utilization of the instrument, including service agreements and full-time Ph.D. mass spectrometrists to operate the instrument. The long-term impact to the University of Utah and regional institutions will be addition of new mass spectrometry resources for the University scientific and medical research community. This state-of-the-art mass spectrometry will stimulate new research projects and innovations for many years. The analytical power of the Maxis HD instrument will play a major role in accelerating research in many areas, particularly, proteomics, natural-product research, and many drug-delivery systems under investigation at the University.